The present invention relates to a unique electrical device and a method of making the same, which device and method have their most important, but not only, utility in the manufacture of plug-in relays commonly used in automobiles.
Plug-in relays have been made for many years in a manner which is not adaptable to completely automated mass projection techniques. As is common in the manufacture of all types of relays and other electromagnetic devices, unless the parts thereof are made to extremely close and therefore expensive tolerances, some manual adjustment or machining operation has generally been required to finally produce an electromagnetic device which meets the customer's specifications. The manufacture of relays for automobile applications requires the seemingly incompatible requirements of low unit cost with high reliability. With the relay design and manufacturing techniques heretofore utilized, a 75% acceptable yield on the completed relays coming off the assembly line was considered highly satisfactory.
There has been an obvious need to decrease the unit cost of such relays without sacrificing their reliability. The present invention has provided a unique design of and method of making a plug-in relay or the like which produce acceptable yields well in excess of 90%, and at a lower unit cost of manufacture than previous designs, because of the unique relay design involved which makes possible a unique fully automated assembly and adjustment procedure which does not require close tolerances of the parts.